   (signal-deps [s] "returns the set of \"parent\" signals on which this signal depends")
   (parents-map [s])
   (kids-map [s])
-  (topsort [s])
-  (-get-graph-meta [s k]))
+  (topsort [s]))
 
 (defn signal?
   "returns `true` if the argument satisfies `SignalProtocol`, `false` otherwise"

(defrecord SignalDefinitionMetadata
  [parents-map kids-map topsort])

(defrecord SignalDefinition
  [init-fn sources relayed-event-topic msg-fn deps event-sources]
  SignalProtocol

                (when (= relayed-topic (topic event))
                  (fresh (value event)))))
    opts))

(defn make-signal
  "Takes a map of opts and returns a signal."
